What a Medico-Legal Report Should Contain: The CPR 35 Checklist

In psychiatric medico-legal practice, the quality of an expert report can influence litigation outcomes. Civil Procedure Rules Part 35 (CPR 35) and its Practice Direction govern expert evidence in civil claims in England and Wales. A compliant report must balance clinical rigour with legal relevance. This guide outlines the essential components of a psychiatric medico-legal report under CPR 35. Other forums have their own rules: Part 19 of the Criminal Procedure Rules 2025 in criminal cases, Part 25 of the Family Procedure Rules and its Practice Directions in family proceedings, and Part 15 of the Court of Protection Rules 2017 in the Court of Protection.

1. CPR 35 Compliance: The Foundation

CPR 35.10 and paragraph 3 of Practice Direction 35 set out the form and content of an expert report. Key requirements include:

• Details of the expert’s qualifications and experience relevant to the issues in the case.
• Details of any literature or other material relied upon in forming opinions.
• A summary of the range of opinions on the matters addressed, with reasons for the expert’s own view.
• A statement that the expert understands, and has complied with, their duty to the court, which overrides any obligation to the instructing or paying party (CPR 35.3 and 35.10(2)).
• A statement of truth in the form set out in paragraph 3.3 of Practice Direction 35.

In psychiatric cases, the expert must clarify their sub-discipline. For example, a report on diminished responsibility under the Homicide Act 1957 usually calls for forensic psychiatric expertise, while a personal injury claim involving post-traumatic stress disorder (PTSD) may necessitate input from a neuropsychiatrist or clinical psychologist trained in trauma assessment.

2. Clinical Context: Psychiatric and Psychological Frameworks

Diagnostic Criteria and Psychometric Tools

A sound medico-legal report must reference established diagnostic frameworks. For psychiatric conditions, the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) and the International Classification of Diseases, Eleventh Revision (ICD-11) are the primary standards. For PTSD claims, the report should address DSM-5 Criteria A (exposure to trauma) through to H, including duration (Criterion F). In asylum cases, the Istanbul Protocol may guide trauma assessments.

Psychometric testing can strengthen diagnostic validity. Common tools include:

• PTSD: PCL-5, CAPS-5.
• Malingering: SIMS, TOMM, MMPI-2-RF.
• Cognitive Function: WAIS-IV, MoCA, ACE-III.
• Neurodevelopmental Disorders: ADOS-2, DIVA-5.

In criminal cases, the report may need to address the M’Naghten Rules (insanity defence) or the Pritchard criteria (fitness to plead). For diminished responsibility, the expert must evaluate whether an abnormality of mental functioning, arising from a recognised medical condition, substantially impaired the defendant’s ability to understand the nature of their conduct, form a rational judgment or exercise self-control, and whether it provides an explanation for the killing (s.2 Homicide Act 1957, as amended by s.52 Coroners and Justice Act 2009). The HCR-20v3 or Risk Matrix 2000 may assess future risk in secure settings.

Sub-Discipline Specialisation

Psychiatric medico-legal reports must align with the sub-discipline. Key distinctions include:

• Forensic Psychiatry: Criminal responsibility, risk assessment (e.g., HCR-20v3), and Mental Health Act disposals (e.g., Section 37/41).
• Child and Adolescent Psychiatry: Parental capacity assessments, attachment theory (Adult Attachment Interview), and fabricated or induced illness (FII).
• Perinatal Psychiatry: Postpartum psychosis, severe postnatal depression, and substance misuse impact on parenting (NICE CG192).
• Neuropsychiatry: Traumatic brain injury, functional neurological disorder (FND), and chronic pain syndromes. The eggshell skull principle (Smith v Leech Brain [1962]) may apply where pre-existing vulnerabilities are exacerbated.
• Old Age Psychiatry: Capacity assessments under the Mental Capacity Act 2005, dementia screening (ACE-III, MoCA).

3. Legal Relevance: Aligning Clinical Findings with Legal Tests

Causation and Prognosis

In personal injury and clinical negligence claims, the expert must address causation and prognosis. The report should distinguish between acceleration of symptoms and material contribution to harm. For example, in a PTSD claim following a road traffic accident, the expert must clarify whether the trauma caused the disorder or exacerbated a pre-existing vulnerability. The usual test is ‘but for’; the material contribution test in Bailey v Ministry of Defence [2008] EWCA Civ 883 may apply where several factors contributed and medical science cannot establish but-for causation.

Prognosis should be evidence-based. In chronic pain cases, the report may reference the biopsychosocial model, while in PTSD, it may discuss recovery likelihood with trauma-focused cognitive behavioural therapy (TF-CBT) or EMDR (NICE NG116).

Capacity and Best Interests

Under the Mental Capacity Act 2005, capacity is decision-specific and time-specific. The report must apply the principles in section 1 of the Act and the test in sections 2 and 3: whether the person is unable to make the decision because of an impairment of, or a disturbance in the functioning of, the mind or brain. For capacity to conduct proceedings, CPR Part 21 adopts the Act’s definition, and Masterman-Lister v Brutton & Co [2002] EWCA Civ 1889 and Dunhill v Burgin [2014] UKSC 18 remain the leading authorities. For fluctuating capacity, the expert should document variability in executive function, as seen in bipolar disorder or borderline personality disorder.

In Court of Protection matters, the COP3 form requires a structured assessment of the individual’s ability to understand, retain, use or weigh, and communicate relevant information. The expert must avoid conflating diagnosis with incapacity; for example, autism spectrum disorder (ASD) does not automatically imply incapacity.

Clinical Negligence: Breach and Causation

In clinical negligence claims, the expert gives an opinion, by reference to the Bolam and Bolitho tests, on whether the standard of care fell below that of a responsible body of medical opinion; whether there was a breach is for the court. For example, in a missed diagnosis of postpartum psychosis, the report should evaluate whether the failure to conduct a specialist assessment breached NICE guidance (CG192).

Causation is usually decided on the ‘but for’ test, with material contribution (Bailey) as a limited exception; damages for the loss of a chance of a better outcome are not recoverable in clinical negligence personal injury claims (Gregg v Scott [2005] UKHL 2). In suicide risk cases, the expert may assess whether a failure to assess the patient for admission, including detention under the Mental Health Act 1983, contributed to the outcome.

4. Common Pitfalls and How to Avoid Them

Diagnostic Overreach

Experts must avoid overdiagnosing conditions based on limited evidence. In asylum cases, PTSD symptoms may overlap with cultural expressions of distress. Psychometric testing (e.g., MMPI-2-RF, TOMM) can help mitigate uncertainty, but no single test is definitive.

Malingering and Symptom Validity

In criminal, personal injury, and immigration cases, the expert must consider malingering. Indicators include:

• Inconsistencies between reported symptoms and observed behaviour.
• Over-endorsement of rare symptoms on psychometric tests (e.g., SIMS).
• Failure on symptom validity tests (e.g., TOMM).
• Discrepancies with collateral information (e.g., medical records).

The expert should present findings neutrally, e.g., “The pattern of responses on the SIMS raises concerns about symptom exaggeration.”

Prognosis Uncertainty

Prognosis must be evidence-based and caveated where uncertainty exists. For example, in chronic pain cases, the expert should acknowledge treatment limitations and potential long-term disability.

Sub-Discipline Confusion

Instructing the wrong sub-discipline can undermine a case. For example, a general adult psychiatrist may lack expertise to assess autism spectrum disorder in adults, where a specialist in neurodevelopmental disorders (using ADOS-2) is required.

5. Practical Guidance for Solicitors

Instructing the Right Expert

Solicitors should match the expert’s sub-discipline to the case issues. Key considerations include:

• Criminal Cases: Forensic psychiatrist for fitness to plead or risk assessment.
• Family Cases: Child and adolescent psychiatrist for parental capacity.
• Personal Injury: Neuropsychiatrist for traumatic brain injury or PTSD.
• Clinical Negligence: Old age psychiatrist for dementia-related capacity issues.
• Capacity Cases: Neuropsychiatrist for brain injury or forensic psychiatrist for fluctuating capacity.

Preparing Instructions

Clear instructions are critical. The letter of instruction should:

• Specify the legal test(s) the expert must address (e.g., Bolam/Bolitho).
• Provide all relevant documents (medical records, witness statements).
• Clarify whether the expert is instructed as a single joint expert (SJE) under CPR 35.7; each instructing party must send a copy of its instructions to the other instructing parties (CPR 35.8).
• Request a statement of compliance with CPR 35 and Practice Direction 35.

Reviewing the Report

Solicitors should scrutinise the report for:

• Compliance: Does the report meet CPR 35.10 requirements?
• Clarity: Are clinical terms explained for a non-medical audience?
• Relevance: Does the report address the legal issues (e.g., causation, capacity)?
• Balance: Does the expert acknowledge alternative opinions and limitations?

Part 35 Questions and Joint Statements

Under CPR 35.6, parties may put written questions to the expert. These should focus on clarifying the report. In cases with multiple experts, a joint statement (CPR 35.12) may be required to identify areas of agreement and disagreement. The expert must approach joint statements impartially, prioritising their duty to the court.